The transport of deleterious/potentially deleterious gases and/or the transport/removal of same from spaces so characterized is an important, oftentimes critical operation. For example, and without limitation, the venting of high-temperature, particular laden, toxic, noxious, corrosive, etc. “gases” or fumes from work places such as laboratories, industrial or chemical processing areas or other environments such as tunnels are well known. Heretofore, and generally, such fumes have been either guided to a tall exhaust stack whereby they are discharged at a height well above ground/roof level, or, during the process of evacuating such fumes, make-up or “fresh” air is introduced so as to mix and thereby dilute the contaminated air, with a high velocity roof top discharge of the diluted air commonplace.
In the context of direct drive tubular inline fan housings/assemblies, traditionally they have been characterized by a so called “bifurcated” design which is intended to isolate, and to some degree cool a fan motor from the contaminated air stream, as well as single-thickness vanes to support the fan motor and “straighten” the air stream “swirl” downstream of the fan impeller, see e.g., U.S. Pat. No. 7,320,363 B2 (Seliger et al.), incorporated herein by reference in its entirety. Moreover, in the context of induced flow fans characteristic of chemical, industrial, manufacturing fume exhaust operations, such direct drive tubular inline fan housings/assemblies are characterized by contraction nozzles for high-speed discharge, and windbands for dilution of fume efflux with ambient air, see e.g., Seliger et al.
Further still, in the context of induced flow fan assemblies, fume exhaust accessories include, and may not be limited to, multiple nozzles of differing outlet areas to accommodate/achieve operating points/velocities believed advantageous, an isolation damper to prevent flow reversal through an idle fan in a parallel fan configuration of a plenum assembly, a bypass damper to maintain nozzle outlet velocity by drawing upon additional ambient air when efflux flow is reduced in a variable exhaust system, and/or a weather management system to prevent precipitation ingress to the system, structures thereof and the structure within which the assembly is deployed.
In as much as apparent improvements have been made with regard to service/maintenance of components of such systems and marginal efficiencies with regard to operating efficiencies and sound attenuation for such systems, it is nonetheless believed that heretofore known functionality may be achieved with a simplified structure/assembly, e.g., a fan housing, which circumvents, eliminates or at least reduces what is believed to be unnecessary momentum and energy losses attendant to any of the functions of “swirl” straightening, motor cooling/protection, high-speed upblast discharge, and/or fume efflux dilution, especially at high airflow rates, while at least maintaining present industry efficiencies as to operation and/or sound output. Moreover, in relation to induced flow fan accessories (i.e., the functional objectives thereof), it is believed that such function can be retained while nonetheless eliminating heretofore known structures owing to, among other things, synergistic effects having origins in Applicant's simplified structure/assembly.